THE ACTION OF VERATRUM ON THE RENAL CIRCULATION OF THE DOG

¹ Department of Physiology, University of North Carolina School of Medicine, Chapel Hill, N. C.

1. The effects of single intravenous injections of Veratrone upon the blood pressure and renal hemodynamics of anesthetized dogs having one kidney acutely denervated have been studied. Data from six eight-hour experiments are presented.

2. Changes in renal plasma flow and glomerular filtration rate in the innervated and denervated kidneys were very similar. Both functions decreased when the blood pressure fell immediately after the drug was injected. As the blood pressure recovered, there was a transient increase in PAH excretion interpreted as a flushing of stagnant tubules. There was little evidence of renal vasodilatation.

3. Two dogs were given preliminary doses of atropine sulfate intravenously in an attempt to prevent the bradycardia which follows veratrum injection. In both animals the renal plasma flow failed to recover to the same degree as the blood pressure.

4. Similarly, two dogs were vagotomized. Vagotomy resulted in no important change in the veratrum effect upon blood pressure or renal hemodynamics.

5. Veratrone caused a decrease in urine volume; U/P ratios for creatinine indicated an increase in tubular reabsorption of water which persisted longer than the decrease in blood pressure, glomerular filtration rate and renal plasma flow. There was no consistent difference between innervated and denervated kidneys.

6. Despite anesthesia and surgical trauma there was no convincing evidence of vasoconstriction in the innervated kidneys during the control periods. Significantly lower glomerular filtration rates and renal plasma flows in innervated as compared with denervated kidneys were seen in only four of twelve control observations.

7. It appears that the effects of veratrum upon the renal circulation do not depend upon the extrinsic renal nerves, either through sympathetic nerves or through vasodilator nerve fibers accompanying the sympathetic nerves.